Rough idle when stopped in drive

[Ward83]

My car has developed a pretty rough idle, but only when stopped in drive. As soon as I start moving and get the revs up, it's smooth. It also feels smooth in neutral or park. But when sitting at a stoplight, it vibrates the entire car. I have replaced the spark plugs, but that didn't make any difference. I also replaced the top two motor mounts which helped some, but not completely. I will be replacing the coils soon. Does this sound like the common EGR valve issue, or could it be something else?

 

[The_big_dill]

Egr.

 

[kms1990]

egr or vacuum leak somewhere. clean your throttle body and idle air control valve as well

 

[pcb]

I'd try half a can of Seafoam in the gas. It may be dirty injectors.

I do my car as soon as I get a bit of vibration at idle. It clears it right up.

 

[kms1990]

I'd try half a can of Seafoam in the gas. It may be dirty injectors.

I do my car as soon as I get a bit of vibration at idle. It clears it right up.

good idea, i run half a can in the gas and the other through the vacuum line on the brake booster every oil change keeps the idle smoother and seems to help mpg some

 

[fortworthmatt]

Mine does the same thing sometimes. I have recently cleaned the egr, replaced the spark plugs, and did a seafoam treatment through the brake vacum line. It is better but still rattles the spoiler brake light.

 

[kms1990]

Mine does the same thing sometimes. I have recently cleaned the egr, replaced the spark plugs, and did a seafoam treatment through the brake vacum line. It is better but still rattles the spoiler brake light.

thats a little much, mine always has some rattle at idle. it has since my dad bought it in 05 and it runs just fine the motor in these cars is gruff and loud and shakes some, its just unrefined. its reliable though. i have all new mounts and the car is in rude health so i know even in 100% health it rattles at idle a little try a k and n drop in filter i have one and it does not rattle as much as when i put a paper filter in, i guess because its less restrictive.